Method for spray forming of tubular bodies



s- 968 c. H. HOWELL, JR 3,397,732

METHOD FOR SPRAY FORMING OP TUBULAR BODIES Filed Jan. 5, 1966 Cleves H. Howell Jr.,

United States Patent 3,397,732 METHOD FOR SPRAY FORMING 0F TUBULAR BODIES Cleves H. Howell, Jr., Huntsville, Ala., assignor to the United States of America as represented by the Secretary of the Army Filed Jan. 3, 1966, Ser. No. 518,493 4 Claims. (Cl. 164-46) ABSTRACT OF THE DISCLOSURE A method for forming tubular bodies by spraying molten metal on a collapsible mandrel as the spray for the molten metal is moved relative to the mandrel, working the metal after it has been sprayed on the mandrel and removing the mandrel from the finished tubular body.

The invention described herein may be used by or for the Government for governmental purposes without the payment of any royalty thereon.

In the past, generally tubular or cylindrical bodies have been formed by various forging, rolling, stamping, machining, welding, riveting, folding and other methods. However, there is a need for a method by which a tubular body, such as a rocket motor case and nozzle, can be formed as a continuous body by spraying molten metal on a form.

Therefore, it is an object of this invention to provide a method by which tubular bodies such as rocket motor cases and nozzles can be sprayed from molten metal.

Another object of this invention is to work the metal after being sprayed onto a mandrel to produce tubular bodies of varying degrees of strength, malleability, hardness and thickness even though the same parent metallic material is used.

A further object of this invention is to work the sprayed metal with shear spinning wheels by moving the shear spinning wheels down the mandrel and over the sprayed metallic material.

Still another object of this invention is to provide a method of making generally tubular bodies from several difierent metallic materials by applying layers of different materials.

A still further object of this invention is to provide a method by which very thin walled and seamless bodies can be produced.

In accordance with this invention, the forming of the generally tubular bodies is carried out by providing a turning lathe type mechanism with a removable or collapsible type mandrel mounted for rotation by the turning lathe. A metal spraying device is mounted for movement longitudinally along an axis parallel to the removable mandrel to spray molten metal on the mandrel as the spraying device is moved alongside the mandrel. Shear spinning wheels are mounted on the metal spraying device or adjacent structure to work and form the molten metal after it has been sprayed onto the mandrel. When the tubular body has been formed by spraying and working, the tubular body is separated from the removable or collapsible mandrel.

In the accompanying drawing forming a part of this specification:

The single figure of the drawing illustrates a perspective view of structure that is used in carrying out this invention.

Referring to the drawing, a turning lathe type mechanism 1 includes a housing portion 3 with suitable motor and drive gear means therein for driving shafts 5 and 7. A beam guide and support 9 is integrally connected with housing 3 to provide support for work mounted thereon. A slide 11 is adjustably mounted on beam 9, and set screw 13 secures slide 11 in position on beam 9. A conventional 3,397,732 Patented Aug. 20, 1968 See collapsible or removable mandrel 15 is connected at one end in a conventional manner to shaft 5 to be rotated thereby. The other end of the mandrel is supported by shaft 17 that is adjustably mounted in a conventional manner on slide 11. A

A material feed housing 19 is threadably mounted on lead or power screw 21 that is connected at one end to shaft 7 and is rotatably mounted at the other end relative to portion 23 of beam 9. Projecting portion 25 of housing 19 has guide means 27 that rides in slot 29 of beam 9 and guides spray housing 19 in longitudinal movement. Arm 31 on an opposite side of housing 19 provides support for shaft 33 about which bobbin 35 is rotatably mounted. Wire 37, made of ferrous or nonferrous metal, is fed through opening 39 in housing 19 to conventional structure inside housing 19, including heating means such as the plasma are type for melting the metal wire and conventional spray means for spraying the molten metal through nozzle 41 onto mandrel 15.

A metal working apparatus 43 is mounted on housing 19 and includes rotatably mounted shear spinning wheels 45 and pneumatically, mechanically or hydraulically operated means in apparatus 43 for adjusting shear spinning wheels 45 relative to mandrel 15 to work sprayed metal or metals of different thicknesses on mandrel 15. Shear spinning wheels 45 may be used for hot or cold working of the sprayed metal. If the shear spinning wheels hot work the metal, heat can be applied to the metal in front of the spinning wheels, or by direct heating means in the spinning wheels.

In operation, with mandrel 15 mounted for rotation, switch 47 is actuated to cause shaft 5 to rotate and in turn rotate mandrel 15. Next, the metal working and spraying apparatuses are made ready, and switch 49 is actuated to cause lead screw 21 to rotate and move housing 19 longitudinally of mandrel 15. After the molten metal is sprayed through nozzle 41 onto mandrel 15 to a given thickness, shear spinning wheels 45 work the metal as the mandrel continues to rotate, and in this manner, tubing of varying degrees of strength, malleability, hardness, and thickness can be produced from the same parent material. After the tube is formed, the removable or collapsible mandrel 15 is removed from the tube that is formed by spraying the molten metal.

It is also possible through this method to use more than one kind or type of metallic material. For example, a material may first be used having extremely good high temperature resistance characteristics yet be lac-king in yield strength. Using this method, it is possible to add a layer of high yield material directly to and bonded with the original material. This method of spraying followed by shear extrusion or hot or cold working may be repeated for any required number of cycles to achieve the desired dimensions or other necessary characteristics.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example only, and that various changes may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

I claim:

1. A method for forming a generally tubular body including: providing a support surface that has the shape of the device to be formed, rotating said support surface about an axis and at a given speed, spraying molten metal on said support surface as the spray for the molten metal is moved longitudinally in relation to the support surface, and removing said support surface from the generally tubular body formed by spraying said molten metal.

2. A method for forming a generally tubular body as set forth in claim 1, wherein said sprayed metal is worked with spinning wheels after said sprayed metal has been deposited on said support surface.

3. A method for forming a generally tubular body as set References Cited forth in claim 1, wherein different metallic materials are UNITED STATES PATENTS sprayed in layers on said support surface to form said generany tubular body. 2,295,702 9/1942 Wis sler 111 -94 x 4. A method for forming a generally tubular body as set 5 2,763,576 9/1956 Behtz et a1 117 105 forth in claim 1, wherein different metallic materials are 3,098,285 7/1963 Kelzenberg et a1 72 82 X sprayed in layers on said support surface to form said generally tubular body, and wherein said sprayed metals are SPENCER OVERHOLSER Pnmary Exammer' worked with wheel means after said sprayed metals have E. MAR, Assistant Examiner. each been deposited on said support surface. 10 

